---
title: "Using Subtrace with Docker"
sidebarTitle: "Docker"
description: "Track requests in your Dockerized app with Subtrace."
icon: "docker"
---

If your app runs in a Docker container, you can use Subtrace to monitor all its
requests. Here's how you can get started:

<Steps>
<Step>
Make the following change to your `Dockerfile` to install and use Subtrace
in your app's Docker image:

```diff
- CMD ["node", "./app.js"]
+ RUN curl -fsSL https://subtrace.dev/install.sh | sh
+ CMD ["subtrace", "run", "--", "node", "./app.js"]
```

</Step>

<Step>
Run your Docker container as you normally would, but add `--cap-add=SYS_PTRACE`:

```diff
- docker run -t -p 3000:3000 node-app
+ docker run -t -p 3000:3000 --cap-add=SYS_PTRACE node-app
```

<Expandable title="example output">
  <img className="rounded-xl" src="/images/docker-link.png" />
</Expandable>

</Step>

<Step>
That's it! Open the `subt.link` URL in your browser to see your app's requests
show up in real time:

<img className="rounded-xl" src="/images/subt-link-example.png" />

</Step>
</Steps>
